1. Field of the Invention
The present invention relates to an electronic-component (xe2x80x9cECxe2x80x9d) supplying apparatus and method and in particular to the art of improving EC supplying efficiency.
2. Related Art Statement
Japanese Patent Application laid open for opposition under Publication No. 2(1990)-53954 discloses an EC supplying apparatus which supplies ECs to an EC mounting apparatus which mounts the ECs on an object such as a printed circuit board (xe2x80x9cPCBxe2x80x9d). The prior EC supplying apparatus includes two tables for supplying the ECs. Each of the two tables is supported by linear table guides provided on a bed, such that each table is movable relative to the bed. Each table supports a plurality of EC supplying cartridges such that respective component-supply portions of the cartridges are arranged along a straight line parallel to the table-guides. A nut which is fixed to each table is threadedly engaged with a feeding screw which extends, on the bed, parallel to the table. guides and which is rotated by a servomotor. Therefore, when each of the two servomotors is driven, the corresponding table is moved via the corresponding feeding screw and nut, so that the cartridges on that table are sequentially moved one by one to a component-supply position where each cartridge supplies ECs from the component-supply portion thereof.
Since the prior EC supplying apparatus includes not one but two tables, each table may have such dimensions which allow only one table to be used for supplying ECs to such a PCB which does not need more than the cartridges that can be supported by one table, and which require two tables to be used for supplying ECs to such a PCB which needs more than the cartridges that can be supported by one table but does not need more than the cartridges that can be supported by two tables. In the first case, the other table is not used or moved and, in the second case, the two tables may be moved, either alternately or simultaneously, for supplying ECs.
Thus, the tables employed in the above-indicated apparatus have smaller dimensions than those of conventional tables that had been designed to be suitable for such PCBs which need the largest number of cartridges, i.e., the largest number of ECs and/or the largest number of sorts of ECs. Accordingly, the tables of the prior EC supplying apparatus can respond more quickly and can move at higher speeds. Therefore, the EC supplying apparatus enjoys improved work efficiency. In addition, the vibration produced when each table is moved and stopped is reduced, which leads to reducing the possibility that the EC mounting apparatus fails to take (e.g., suck) ECs from the EC supplying apparatus.
However, the prior EC supplying apparatus employs at most two tables. Accordingly, if a greater number of cartridges are needed to supply ECs to a PCB, the two tables are required to have greater dimensions. In such cases, the tables cannot be moved at sufficiently high speeds, which leads to lowering the work efficiency of the EC supplying apparatus.
In the above-described situation, Japanese Patent Application laid open for inspection under Publication No. 6(1994)-342994 discloses an EC supplying apparatus which employs three or more tables for supplying ECs. In this apparatus, too, linear table guides are provided on a bed, and three or more tables are supported on the table guides such that each table is movable relative to the bed. Each table supports a plurality of EC supplying cartridges such that respective component-supply portions of the cartridges are arranged along a straight line parallel to the table guides. In addition, two carrier guides which extend parallel to the table guides are provided on the bed, and two carriers are supported on the carrier guides such that each carrier is movable relative to the bed. A nut which is fixed to each carrier is threadedly engaged with a feeding screw which extends, on the bed, parallel to the table guides and which is rotated by a servomotor. Each of the two carriers includes an engaging device which is disengageably engageable with one corresponding table, or each of two or more corresponding tables, and moves the one or each table to a component-supply area as an intermediate area on the bed in a direction parallel to the table guides, so that the one or each table supplies ECs in the component-supply area.
Since the above-indicated second prior apparatus employs two carriers, two tables of the three or more tables can simultaneously be moved by the two carriers, respectively. Thus, the second prior apparatus can advantageously supply ECs like the first prior apparatus wherein the two tables are directly driven and moved. In addition, each carrier can selectively be engaged with each of two or more tables. Therefore, the second prior apparatus can employ three or more tables for supplying ECs, even if it employs only two carriers. Accordingly, the tables employed in the second apparatus can have still smaller dimensions and can move at still higher speeds, which leads to further improving the work efficiency of the apparatus.
However, since the second prior apparatus has only two carriers, there are some cases where it may need much time to change a table which is currently supplying ECs in the component-supply area, to another table which is next to supply ECs in the same area. If, after one of the two carriers retracts, from the component-supply area, a first table which has completed the supplying of ECs, and before the same carrier engages a third table to follow a second table which is now supplying ECs in the component-supply area, and prepares for moving the third table to the component-supply area, the second table engaged with the other carrier completes the supplying of ECs, it needs a wasteful time after the second table completes the EC supplying and before the third table is ready for EC supplying.
It is an object of the present invention to provide EC supplying apparatus and method which employ small tables and quickly change the tables with one another for supplying ECs.
It is another object of the present invention to provide an EC supplying apparatus which employs carriers and drive devices each of which moves a corresponding one of the carriers and each of which is constructed by major parts provided apart from the corresponding one carrier.
It is another object of the present invention to provide an EC supplying apparatus which employs tables and an exclusive table retracting device which retracts the tables to a waiting area.
It is another object of the present invention to provide a table retracting device at low production cost.
It is another object of the present invention to provide an EC supplying apparatus which supplies ECs in a plurality of modes.
According to the present invention, there is provided electronic-component supplying apparatus and method which have each one of the technical features which will be described below in respective paragraphs given parenthesized sequential numerals (1) to (14). Any technical feature which includes one or more other technical features does so by a reference at the beginning to the numeral or numerals of the other technical feature or features. Thus, as far as the present invention is concerned, two or more of the technical features (2) to (12) may be combined with each other, if appropriate.
(1) According to a first feature of the present invention, there is provided an electronic-component supplying apparatus, comprising a bed including at least one linear table guide, at least four tables each of which is supported by the table guide such that the each table is movable relative to the bed, the each table supporting a plurality of electronic-component supplying cartridges such that respective component-supply portions of the cartridges are arranged along a straight line parallel to the table guide, the at least four tables including at least one table belonging to a first table group, and at least one table belonging to a second table group, at least three carriers each one of which is movable, independent of the other carriers, through a corresponding one of at least three routes which is associated with the each one carrier exclusively, the each one carrier being stopable at any position on the corresponding one route, the at least three routes extending parallel to one another and the table guide, within a carrier-movement area on the bed which is an intermediate area on the bed in a direction parallel to the table guide, a plurality of carrier-related engaging devices and a plurality of engageable portions each of which is disengageably engageable with at least one corresponding engaging device of the engaging devices, one of (a) each of the at least four tables and (b) each of the at least three carriers supporting a corresponding one of the engaging devices, the other of (a) the each of the at least four tables and (b) the each of the at least three carriers including a corresponding one of the plurality of engageable portions, a first table retracting device which retracts the at least one table of the first table group, to a first waiting area on the bed which is one of two side areas on both sides of the intermediate area on the bed in the direction parallel to the table guide, and a second table retracting device which retracts the at least one table of the second table group, to a second waiting area on the bed which is the other side area on the bed. In the present electronic-component (xe2x80x9cECxe2x80x9d) supplying apparatus, the respective exclusive routes for the three or more carriers are provided- in the carrier-movement (xe2x80x9cCMxe2x80x9d) area such that the exclusive routes extend parallel to each other. Thus, each one of the carriers can pass by the other carriers. The three or more carriers are engaged,. as needed, with appropriate ones of the four or more tables for concurrently carrying three task, i.e., moving a table for supplying ECs in the CM area, retracting another table which has completed the supplying of ECs from the CM area, and preparing yet another table which is to supply ECs next. The supplying of ECs may be carried out by moving a single table at one time. However, as will be described later on the preferred embodiments of the invention, it may be carried out such that while a first table is moved for supplying ECs in the CM area, a second table which is to supply ECs next follows the first table at acceleration and deceleration whose absolute values are smaller than those of the first table. That is, the supplying of ECs may be carried out by moving the first and second tables in the CM area as if they were a single table. During this, a third table which has completed the supplying of ECs may be retracted from the CM area, and a fourth table may be prepared for following the second table in the CM area after the first table completes the EC supplying. Alternatively, the supplying of ECs may be performed by moving two tables in synchronism with each other as if they were a single table. Even if two tables may be moved for supplying ECs, it can be said that one of the two tables is waiting for the completion of EC supplying of the other table. That is, even if two tables may be moved for supplying ECs, they will not simultaneously complete their EC supplying, i.e., will complete their EC supplying at different timings. Therefore, while one of the two tables which has completed the EC supplying is retracted, the other table is supplying ECs, and another table is prepared for supplying ECs. Each of the carriers may be of a xe2x80x9cdrivenxe2x80x9d type, as will be described on the preferred embodiments of the invention, which is moved when a feeding screw is rotated which is provided on the bed for the each carrier via a nut which is fixed to the each carrier and is threadedly engaged with the screw. Alternatively, each carrier may be of an xe2x80x9cautoxe2x80x9d type which is moved when an electric motor mounted on the each carrier is driven to rotate a nut which is rotatably mounted on the each carrier and is threadedly engaged with a feeding screw fixed to the bed. Each carrier may be of another xe2x80x9cautoxe2x80x9d type which is provided by a movable element of a linear motor. The carrier-related engaging devices may be provided on either the carriers or the tables, respectively. The total number of the engaging devices provided on the respective carriers is smaller than that of the engaging devices provided on the respective tables, if the total number of the carriers is smaller than that of the tables. Each of the EC supplying cartridges may include a supply reel around which an EC tape holding ECs at a regular interval in the longitudinal direction thereof is wound, and a feeding. device which intermittently feeds the EC tape at a feeding pitch equal to the regular interval of EC holding of the EC tape so that the ECs are moved one by one to the EC-supply portion of the each cartridge, i.e., EC-pick-up portion of the same from which the EC is picked up by an EC pick-up apparatus. Alternatively, each cartridge may include a box which accommodates an EC tape and a drawing device which intermittently draws the EC tape at a drawing pitch. The cartridges are not limited to those which supply ECs in the form of EC tapes. For example, each cartridge may include a casing in which ECs are arranged in an array, and a vibrating or tilting device which vibrates or tilts the casing so as to move and supply the ECs. The first and second table retracting devices may be provided by exclusive table retracting devices, or alternatively by the carriers. In the former case, the exclusive table retracting devices receive the tables from the carriers, and retract them to the waiting areas. In the latter case, the respective exclusive routes provided in the CM area for the three or more carriers are extended to the first and second waiting areas on both sides of the CM areas, so that the carriers may move to the waiting areas. Within the CM area, each of the carriers can be stopped at any desired position for supplying an EC but, within the waiting areas, the carriers function as the table retracting devices for moving the carriers from the CM area to the waiting areas. In the present apparatus, the four or more tables are divided into a first and a second table group, and the first and second table retracting devices retract the tables of the first and second table groups to the first and second waiting areas, respectively. As will be described on the preferred embodiments of the invention, the supplying of ECs may be carried out by using only one of the two tables groups, while the other table group remains waiting in the corresponding waiting area, permitting an operator to changing one or more of the cartridges on each table with another or other cartridges. The four or more tables may be divided into two groups each including the same number of tables or may be divided to two groups including different numbers of tables, respectively. Thus, in the present EC supplying apparatus, a number of EC supplying cartridges are divided into four or more groups, which are mounted on the four or more tables, respectively. Therefore, even in the case where it is needed to supply a greater number of ECs or a greater number of sorts of ECs, it is not needed to employ tables with greater dimensions. Thus, the tables can be moved at high speeds to supply ECs quickly. Since the three or more carriers are simultaneously used for moving a first table for supplying ECs, having a second table waiting for next supplying ECs, and retracting a third table which has completed the EC supplying, the second table can start supplying ECs immediately after the first table completes the EC supplying. Accordingly, the EC supplying operation is carried out without needing any wasteful time. In the case where the second table is also moved to follow the fist table which is being moved for supplying ECs, the second table can replace the first table in a very short time when the first table completes the EC supplying. Thus, the EC supplying efficiency of the present apparatus is much improved.
(2) According to a second feature of the invention which includes the first feature (1), the EC supplying apparatus further comprises a same number of feeding screws as a number of the at least three carriers, the feeding screws being provided on the bed such that the feeding screws extend parallel to one another and the table guide, a plurality of nuts each, of which is fixed to a corresponding one of the carriers and is threadedly engaged with a corresponding one of the feeding screws, and a plurality of drive devices each of which rotates a corresponding one of the feeding screws which is associated with the each drive device exclusively. In the present apparatus, the carriers are moved as the corresponding feeding screws are rotated by the corresponding drive devices, respectively. It is only the nuts that are respective parts of carrier driving devices and are mounted on the carriers. Thus, each carrier enjoys a light mass and accordingly can be moved at high speeds. The EC-supply efficiency of the present apparatus is thus improved.
(3) According to a third feature of the invention which includes the first feature (1) or the second feature (2), the first table retracting device comprises a first movable member which is movable in the direction parallel to the table guide, at least one first-movable-member-related engaging device and a plurality of first engageable portions each of which is disengageably engageable with the at least one first-movable-member engaging device, one of (a) the first movable member and (b) the at least two tables of the first table group supporting the at least one first-movable-member-related engaging device, the other of (a) the first movable member and (b) the at least two tables of the first table group supporting the plurality of first engageable portions, and a first moving device which moves the first movable member within a first composite area provided by the carrier-movement area and the first waiting area, and the second table retracting device comprises, a second movable member which is movable in the direction parallel to the table guide, at least one second-movable-member-related engaging device and a plurality of second engageable portions each of which is disengageably engageable with the at least one second-movable-member engaging device, one of (a) the second movable member and (b) the at least two tables of the second table group supporting the at least one second-movable-member-related engaging device, the other of (a) the second movable member and (b) the at least two tables of the second table group including the plurality of second engageable portions, and a second moving device which moves the second movable member within a second composite area provided by the carrier-movement area and the second waiting area. In the present apparatus, the tables are engaged with the movable members when the engaging devices are engaged with the engageable portions, and the tables are moved with the movable members. The at least one first- or second-movable-member-related engaging device may be either a single engaging device, or the same number of engaging devices as the number of the tables, in the case where the engaging device or devices is or are supported by the first or second movable member. In the latter case, all the tables of the first or second table groups may be engaged with the first or second movable member via the engaging devices on the movable member and the engageable portions of the tables, so that all the tables may be moved from a component-supply (xe2x80x9cCSxe2x80x9d) area to the first or second waiting area, or from the waiting area to the CS area. The movable-member-related engaging devices and the engageable portions may function for positioning the tables being not engaged with the carriers, relative to the bed. In this case, one or more exclusive table positioning devices may not be employed. In the above-indicated former case, each of the tables of the first or second group can be retracted to the first or second waiting area, by iteratively reciprocating the first or second movable member between the CM area and the first or second waiting area. In this case, it is preferred that one or more exclusive table positioning devices be provided for positioning, relative to the bed, the table or tables which waits or wait in the first or second waiting area, for preventing undesirable movements of. the tables in the waiting area. In the case where the tables support the first- and second-movable-member-related engaging devices, respectively, those engaging devices may also function as the carrier-related engaging devices for engaging the tables and the carriers with each other. In this case, the total number of the engaging devices is reduced. On the other hand, in the case where the movable-member-related engaging devices and the engageable portions engageable therewith may be provided independent of the carrier-related engaging devices and the engageable portions engageable therewith. In this case, the movable-member-related engaging devices can be engaged with, and disengaged from, the engageable portions therefor while simultaneously the carrier-related engaging devices are engaged with, and disengaged from, the engageable portions therefor. In the case where the tables support the first- and second-movable-member-related engaging devices, respectively, the first or second movable member may include only a single engageable portion which is engageable with each of the first- or second-movable-member-related engaging devices.
(4) According to a fourth feature of the invention which includes the third feature (3), the first moving device comprises a plurality of first rotatable members which are provided at opposite ends of the first composite area and each of which is rotatable about an axis line extending in a direction perpendicular to the table guide, at least one first wound-on member which is wound on the first rotatable members so as to connect the first rotatable members and extend parallel to the table guide, and a first drive device which rotates at least one of the first rotatable members, the first movable member being connected to a portion of the first wound-on member, and wherein the second moving device comprises a plurality of second rotatable members which are provided at opposite ends of the second composite area and each of which is rotatable about an axis line extending in a direction perpendicular to the table guide, a second wound-on member which is wound on the second rotatable members so as to connect the second rotatable members and extend parallel to the table guide, and a second drive device which rotates one of the second rotatable members, the second movable member being connected to a portion of the second wound-on member. In the present apparatus, the first or second movable member is moved, and the tables are moved, when the first or second rotatable members are rotated and the first or second wound-on member is moved or circulated. The first or second rotatable members may be timing pulleys, V-type pulleys, sprockets, or the like, and the first or second wound-one member may be a timing (cog) belt, a V-type belt, a chain, or the like. The first or second drive device may include a servomotor as a drive source. However, it is not essentially needed to employ, as the drive source, a servomotor or any other electric motor whose rotation angle can be controlled with accuracy. A common electric motor can be employed as the drive source. The accuracy with which the tables are stopped in the first or second waiting area may be lower than that with which the tables are stopped in the CM area for supplying ECs, and the first or second moving device may be provided by the first or second rotatable members, the first or second wound-on member, and the first and second drive device. Thus, the first or second table retracting device may be produced at low cost.
(5) According to a fifth feature of the invention which includes any one of the first to fourth features (1) to (4), the EC supplying apparatus. further comprises a component-supply control device which controls the carriers, the carrier-related engaging devices, and the first and second table retracting devices in a single-group mode in which the at least one table of one of the first and second groups iteratively carries out a first sequence of movements for supplying electronic components while the at least one table of the other group is not moved, and a two-group mode in which the tables of both of the first and second groups iteratively carry out a second sequence of movements for supplying electronic components. The single-group mode may be a first mode in which the sorts of ECs supplied by the first table group are the same as those of ECs supplied by the second table group, or a second mode in which at least one of the sorts of ECs supplied by the first table group is different from the sorts of ECs supplied by the second table group. In the second mode, the above-indicated other table group may wait in the corresponding waiting area for a long time in some cases, or for a short time in other cases. In the case where the one table group supplies ECs for being mounted on each of a number of successive PCBs of a same sort, the other table group waits for a long time, thereby allowing an operator to change the cartridges with other cartridges or replenishing the cartridges with ECs. On the other hand, in the case where ECs are supplied for being mounted alternately on a PCB of a first and on a PCB of a second sort or alternately on a first predetermined number of PCBs of a first sort and on a second predetermined number of PCBs of a second sort, the first and second table groups are frequently changed with each other corresponding to the alternate change of the first and second sorts of the PCBs. Thus, the other table group waits for a short time. In the two-group mode, ECs can be supplied by using the tables of the two groups, i.e., using the greater number of cartridges than the number of cartridges that can be supported by the tables of only one group.
(6) According to a sixth feature of the invention which includes any one of the first to fifth features (1) to (5), the EC supplying apparatus further comprises a carrier control device which controls the carriers such that one of the tables iteratively moves and stops for supplying electronic components and another of the tables follows the one table at an acceleration whose absolute value is smaller than that of an acceleration of the one table and at a deceleration whose absolute value is smaller than that of a deceleration of the one table. In the present apparatus, since the next table which is for next supplying ECs follows the current table which is currently supplying ECs, the next table is moving near the current table and can immediately start supplying ECs, when the current table completes the supplying of the last EC. That is, the current table can be changed with the next table in a very short time. Regarding an EC supplying apparatus which is appropriately designed and produced, this time can be shortened to such a time which is approximate to the time needed to change one cartridge with its adjacent cartridge on each table. In addition, since the next table is moved at acceleration and deceleration whose absolute values are smaller than those of acceleration and deceleration of the current table, the present apparatus produces only smaller vibration and lower noise as compared with an apparatus wherein two tables are moved as a unit at the same acceleration and deceleration.
(7) According to a seventh feature of the invention which includes any one of the first to sixth features (1) to (6), the at least one table guide commonly supports every one of the at least four tables. The present apparatus is advantageous in the case where each of the four or more tables need not pass by the other tables, because the total number of parts needed can be reduced and accordingly the present apparatus enjoys a simple construction.
(8) According to an eighth feature of the invention which includes any one of the first to seventh features (1) to (7), the EC supplying apparatus further comprises at least three carrier guides each of which guides a corresponding one of the at least three carriers and is associated with the corresponding one carrier exclusively. Since the carriers are supported by the carrier guides, respectively, the carriers can move without tilting even while they are not engaged with the tables. Therefore, the carrier-related engaging devices can engage the engageable portions with ease and with stability.
(9) According to a ninth feature of the invention which includes any one of the first to eighth features (1) to (8), the carrier-related engaging devices are provided on the carriers, respectively, and each of the carrier-related engaging devices is engageable with the engageable portion of at least one corresponding table of the tables. The total number of the carrier-related engaging devices respectively provided on the carriers is smaller than that of the engaging devices respectively provided on the tables, in the case where the total number of the carriers is smaller than that of the tables. This contributes to reducing the production cost of the present apparatus.
(10) According to a tenth feature of the invention which includes any one of the first to ninth features (1) to (9), the first table group includes a same number of tables as a number of the tables of the second table group, and each of the first and second table retracting devices retracts the tables of a corresponding one of the first and second table groups, to a corresponding one of the first and second waiting areas. In the case where the four or more, even number of tables are divided into two groups each having the same number of tables, the first and second waiting areas may have the same length in the direction of moving of the tables, and the first and second table retracting devices may have the same construction. For example, the first and second movable members may have the same length, the respective numbers of the first- and second-movable-member-related engaging devices may be equal to each other, and the respective driving forces of the drive sources of the first and second moving devices may be equal to each other. Thus, the first and second retracting devices can be assembled from common parts and accordingly can be produced at low cost and with ease. In addition, the present EC supplying apparatus may be designed as being symmetrical with respect to a component-supply position corresponding to the middle position of the CM area. This contributes to designing the present apparatus with ease.
(11) According to an eleventh feature of the invention which includes any one of the third to tenth features (3) to (10), the first table retracting device further comprises a first guide which guides the first movable member and is associated therewith exclusively, and the second table retracting device further comprises a second guide which guides the second movable member and is associated therewith exclusively, the first guide extends over the first waiting area and at least a portion of the carrier-movement area, and the second guide extends over the second waiting area and at least a portion of the carrier-movement area. Since the first or second table retracting device is required to move the first or second movable member for retracting the tables to the first or second waiting area but is not required to move the movable member over the entirety of the CM area, the length of the first or second guide may be shorter than the sum of respective lengths of the first or second waiting area and the CM area.
(12) According to a twelfth feature of the invention which includes the eleventh feature (11), the first guide extends over the first waiting area and an entirety of the carrier-movement area, and the second guide extends over the second waiting area and an entirety of the carrier-movement area. In the present apparatus, the first or second movable member is movable within the entire CM area, and can retract each table from any position in the CM area to the first or second waiting area.
(13) According to a thirteenth feature of the present invention, there is provided a method of supplying electronic components, comprising the steps of preparing (a) at least four tables each of which is movable, by being guided by at least one common linear guide, in a table-movement area including at least one waiting area and a carrier-movement area in series, (b) at least three carriers each one of which is movable, independent of the other carriers, in a direction parallel to the linear guide, and is passable by the other carriers, and (c) a plurality of electronic-component supplying cartridges each of which stores a number of electronic components of a sort and includes a component-supply portion from which the electronic components are supplied one by one, placing, on each of the at least four tables, at least two electronic-component supplying cartridges of the plurality of electronic-component supplying cartridges, such that the respective component-supply portions of the at least two electronic-component supplying cartridges are arranged along a straight line, and engaging at least three tables of the at least four tables with the at least three carriers, respectively, while keeping the remaining at least one table within the waiting area, and iteratively moving and stopping a first carrier of the at least three carriers within the carrier-movement area, while positioning the component-supply portion of each of the cartridges on the table engaged with the first carrier, at a component-supply position where the each cartridge supplies at least one electronic component from the component-supply portion thereof, and simultaneously moving a second carrier of the remaining carriers, in a manner different from a manner in which the first carrier is moved and stopped, thereby moving the table engaged with the second carrier to replace the table engaged with the first carrier.
(14) According to a fourteenth feature of the invention which includes the thirteenth feature (13), the step of moving the table engaged with the second carrier to replace the table engaged with the first carrier comprises moving the table engaged with the second carrier to follow the table engaged with the first carrier, at an acceleration whose absolute value is smaller than that of an acceleration of the first table and a deceleration whose absolute value is smaller than that of a deceleration of the first table.